1. Field of the Invention
This invention relates to a process for manufacturing fibrous potassium titanate, and more particularly, fibrous potassium tetratitanate or hexatitanate, or a mixture thereof.
2. Description of the Prior Art
A number of processes, such as the flux, hydrothermal, fusion or burning process, are known for the manufacture of fibrous potassium titanate. The flux, fusion or burning process is, among others, considered advantageous for the continuous manufacture of fibrous potassium titanate on a large, industrial scale.
All of these processes, however, have their own disadvantages. The flux process is expensive, since it repairs a flux, and the removal and recovery thereof. The fibers obtained by the fusion process are large in diameter and low in strength, and do not lend themselves to utilization for physical purposes, though they may be suitable for chemical purposes. The burning process produces only short fibers, though it is advantageously a simple process.
The inventor of this invention previously conducted research for the manufacture of long potassium titanate fibers by the flux process, and discovered potassium molybdate and potassium tungstate as a novel flux which could be used for manufacturing long potassium titanate fibers without causing any environmental pollution, as disclosed in Japanese Pat. No. 1,034,519. He tried to clarify the mechanism of the flux growth reaction employing the flux which he had discovered. As a result, he discovered the presence of the dissociation and association reactions involving the reaction between a solid phase of titanium oxide and a liquid phase of potassium oxide at a high temperature to form a solid phase of potassium hexatitanate and a liquid phase of potassium oxide, and the slow cooling thereof causing a solid phase of potassium tetratitanate to grow in long fibers, as represented below: ##STR1##
These reactions were found to require only a small quantity of the flux, since a molten solution of the flux had a catalytic action.
This process has, however, been found to still have the following drawbacks:
(1) The flux is so expensive that even a small quantity thereof adds much to the cost of the materials required by the process;
(2) The equipment required for washing and recovering the flux increases the cost of the facilities required by the process; and
(3) A large quantity of industrial water is required for the operation of any such equipment, and increases the cost of production.